Paint-shield label

ABSTRACT

While in typical enamel protection labels, an adhesive layer lies on each silicone-containing separating layer, from which the first is detachable, according to the present invention the separating area is implemented using a material pairing free of adhesive and silicone.  
     The enamel protection label has two masking layers ( 7   a,    7   b ), more masking layers are also possible. The upper masking layer ( 7   b ) is attached using an adhesive layer ( 10   b ) onto the separating layer ( 8   b ) made of transparent UV-cured screenprint enamel. This enamel is applied to the lower masking layer ( 7   a ), made of a plastic film which is not pretreated further. The separating area ( 9   b ) functionally assigned to the upper masking layer ( 7   b ) represents the boundary area between separating area ( 8   b ) and lower masking layer ( 7   a ), along which the detachment for removing the upper masking layer ( 7   b ) is performed. After the upper masking layer ( 7   b ) is removed, the imprint ( 2 ) is visible through the lower masking layer ( 7   a ), which lies protected under the masking layer ( 7 ) during the first enameling step, and the sealing layer ( 6 ). The position and function of the initially remaining lower masking layer ( 7   a ), adhesive layer ( 10   a ), separating layer ( 8   a ), and separating area ( 9   a ) functionally assigned to the lower masking layer ( 7   a ) during and after the second enameling step are analogous.

The present invention relates to an enamel protection label, inparticular an enamel protection label for covering text, image, and/orcode information in an enameling process, which has a transparentsealing layer, a self-adhesive coating positioned underneath the sealinglayer, and at least one removable masking layer, which covers thesealing layer at least in the region of the text, image, and/or codeinformation and is transparent at least in the region of the coverage ofthe text, image, and/or code information, a separating area of twolayers lying on top of one another being functionally assigned to eachmasking layer in such a way that these layers lying on top of oneanother are separated from one another when the masking layer isremoved.

A label construction of this type for enamel protection applications inmotor vehicle construction is known from EP-A-0065766. This is aplate-shaped code carrier for application on vehicle body parts whichhas optically recognizable information about the type of processing ofthe individual part, the association to a specific motor vehicle, etc.In order that the code carrier remains undamaged and readable after eachof the steps connected with a modern enameling process, such asdegreasing, phosphatizing, priming, and final enameling, it is protectedby multiple transparent plastic masking pieces positioned one overanother. These film pieces are each individually detachable after theparticular steps, so that the information on the code carrier becomesclearly visible again through the particular masking pieces remainingunder the detached film piece. This is technically implemented in thatthe masking pieces each have a transparent adhesive layer on theirbottoms and are attached therewith to a siliconized layer of theparticular film lying underneath. The siliconization has anadhesive-reducing effect and is therefore responsible for the glued-onmasking piece remaining detachable. During the manufacturing of themasking film composite, each plastic film must be subjected to apretreatment before the siliconization, for example, a chemicalroughening by using a primer in order to allow the siliconized layer toadhere to the particular film.

An adhesive composite of the type previously known, in which theself-adhesive individual layers detach from one another at separatinglayers made of silicon-containing separation enamels, is problematic inapplication, since, among other things, released silicone may interferewith the sensitive enameling process and cause enameling flaws. Inaddition, the film pretreatment typically necessary for thesiliconization is complex and costly. In consideration of temperaturesof up to 200° C. occurring during drying steps in the enameling method,different possibilities for alternative achievements of the object inthe framework of the known technology of detaching an adhesive from asubstrate are also problematic. Known adhesives detachable from plasticfilms without siliconization tend to interlock with the substrate whenthey are subjected to temperatures this high.

Because of the problems described, the present invention is based on theobject of providing an enamel protection label of the type described atthe beginning which is at least equal to typical adhesive composites inhandling and functional reliability in the event of high temperaturestress, but also reduces the release of silicone as much as possible.

This object is achieved according to the present invention by an enamelprotection label for masking text, image, and/or code information, whichrepresents a barcode or a part number, for example, which has atransparent sealing layer, a self-adhesive coating positioned underneaththe sealing layer, and at least one removable masking layer, whichcovers the sealing layer at least in the region of the text, image,and/or code information and is transparent at least in the region of thecoverage of the text, image, and/or code information, a separating areaof two layers lying on top of one another being functionally assigned toeach masking layer in such a way that these layers lying on top of oneanother are separated from one another when the masking layer isremoved, and the separating area being adhesive-free.

While in typical enamel protection labels, the separating areas each liebetween an adhesive layer and a separating layer, from which theadhesive layer is to be detachable, in the achievement of the objectaccording to the present invention, the separating area is implemented,in a way completely surprising to those skilled in the art, using anadhesive-free material pairing. The object, which was previously onlyachieved in an unsatisfactory way, of designing an adhesive materiallayer so that it is detachable from its substrate while avoidingsiliconization, even after they have been subjected to unfavorableenvironmental conditions, is thus bypassed.

Preferably, at the particular separating area, a transparent enamelborders a plastic film which has not been subjected to any of thetypical pressure preparation treatments, whether using radiation, coronadischarges, or a chemical primer. Because such a pretreatment isavoided, the adhesion of the enamel to the plastic film is limited, sothat the enamel may be detached to remove the masking layer assigned tothe separating area, but the coherence is sufficient that the overallcomposite does not fall apart at an undesired time. The plastic film maybe the sealing layer in the case of the lowermost masking layer, and inthe case of possible masking layers lying underneath, it may be theparticular next masking layer lying underneath. The avoidance of theotherwise typical pressure preparation treatment also results insimplification and price reduction of the label manufacturing.

The enamel is preferably a UV-curing enamel. Enamels of this type areavailable as silicone-free or at least nearly silicone-free systems,silicone-free systems being especially advantageous in consideration ofthe avoidance of silicone release.

According to an especially preferred embodiment of the presentinvention, the enamel is applied using screen printing. A definedapplication thickness of the enamel may thus be set. This isparticularly advantageous when the enamel layer is glued to the layerlying above it, since the adhesive may thus be reliably prevented frombleeding through to the film, so that the separating area thus remainsadhesive-free according to the present invention.

According to further preferred embodiments of the present invention, theenamel is applied using the letterpress or flexographic printingmethods.

Using the material pairing cited, of a suitable enamel and suitableplastic film, a bond may be provided on the separating area, in a waysurprising to those skilled in the art, which offers sufficientcoherence for the overall composite, but also results in the desireddetachability.

According to an advantageous refinement, underneath the sealing layer, abase layer glued thereto is positioned, whose top is provided with thetext, image, and/or code information to be masked. The self-adhesivecoating to be stuck on the object to be enameled is then advantageouslypositioned on the bottom of the base layer. This base layer thus assumesthe task of the vehicle identification plate or process tracking label.Instead of first attaching an information carrier on the object to beenameled and then attaching the enamel protection label thereto, thesetwo steps may thus be combined in one procedure. This means a savings incomplexity and cost in the manufacturing cycle of the part to beenameled, in particular since in the embodiment described a less precisepositioning of the enamel protection label on the substrate is sometimessufficient, while in contrast the label must otherwise be positioned sothat it precisely covers the information carrier already present. Themanufacture of an information carrier having enamel protection accordingto the present invention already integrated is sometimes morecost-effective than the separate manufacture of information carrier andenamel protection label.

If the information carrier is to be manufactured and appliedindependently from the enamel protection label for certain reasons, thesealing layer itself advantageously carries the self-adhesive coating onits bottom.

According to an especially preferred embodiment of the presentinventions the enamel protection label has multiple masking layerspositioned on top of one another, which are removable one after another.In this way, in a multistep enameling process, after each process stepthe transparent remaining composite lying underneath may be exposed bypulling off the uppermost contaminated, enameled, or cloudy layer for aclear view through to the masked text, image, and/or code information.

According to an advantageous refinement, each masking layer directlyadjoins its particular functionally assigned separating area. In thiscase, adhesive layers between the masking layers and/or between thesealing layer and lowermost masking layer may be dispensed with. Themasking layers are attached to one another and/or to the sealing layerusing curable enamel which is cured after the application of theparticular layer lying thereunder. In this case, the film area locatedunder the enamel layer may be pressure pretreated, but not the film areaof the functionally assigned masking layer lying above it. However, anadhesive layer may also be located between the enamel layer and the filmarea lying underneath. During manufacturing, the masking layer to whichthis separating area is functionally assigned is preferably firstprinted with UV-curing enamel using screen printing and this enamel isthen cured, after which the masking layer is laminated together with thenext film lying underneath, which is adhesive-coated.

According to another advantageous embodiment, each masking layer, withthe exception of the uppermost masking layer, adjoins the separatingarea functionally assigned to the particular next masking layer lyingunderneath. In this case as well, adhesive layers between the maskinglayers and/or between the sealing layer and the lowermost masking layermay be dispensed with. The masking layers are attached to one anotherand/or to the sealing layer using curable enamel, which is cured afterthe application of the particular layer lying above it. In this case,the film area located above the enamel layer may be pressure pretreated,but not the film area of the functionally assigned masking layer lyingunderneath it. However, an adhesive layer may be located between theenamel layer and the film area lying underneath it. Duringmanufacturing, the particular plastic film which is to adjoin thecorresponding separating area is preferably first printed with UV-curingenamel using screen printing and this enamel is then cured, after whichthe adhesive-coated masking layer to which this separating area isfunctionally assigned is laminated over.

The label preferably has at least one removal aid functionally assignedto a particular masking layer. This may be a grip tab shaped onto themasking layer assigned to it or a separate film piece.

The individual layers do not absolutely have to be implemented over theentire area for flawless functioning of the enamel protection label.Particularly in the edge regions, the construction may be altered inorder to obtain local regions of increased or reduced adhesion when thisis expedient. For example, it is especially favorable in the case ofadhesive layers positioned between the masking layers to dispense with aseparating layer in a narrow region adjoining a provided removal aid, sothat there is increased local adhesion between the masking layerassigned to the separating layer and the particular film composite lyingunderneath it. This measure may help avoid premature undesireddetachment of the corresponding masking layer through mechanical effectsduring the enameling process.

Examples of preferred embodiments of the present invention will beexplained in greater detail on the basis of the associated figures. Theillustrations selected are sectional illustrations which are not toscale and are to be seen as purely schematic in this case. Inparticular, the layer thicknesses are greatly enlarged for reasons ofviewability.

FIG. 1 shows an enamel protection label according to the presentinvention attached to a substrate, having a masking layer which islaminated onto an enamel layer using an adhesive,

FIG. 2 shows a label arrangement according to the present inventionhaving two masking layers detachable independently from one another,each of which is laminated onto an enamel layer using an adhesive,

FIG. 3 shows a label arrangement according to the present inventionhaving two masking layers detachable independently from one another,which are attached to the particular layer lying underneath withoutusing adhesive.

In all of the figures, an information carrier 1 printed with opticallyviewable information 2 (text, numbers, a barcode, or something similar)is illustrated, which is attached using an adhesive layer 3 onto asurface 4, of a vehicle body part of a motor vehicle, for example, whichis to be subjected to an enameling treatment. The information carrier 1may either be a part of the enamel protection label as a printed baselayer and be attached therewith to the surface 4, or it may be a vehicleidentification plate or the like which is manufactured separately andapplied to the surface 4 before, the enamel protection label isattached. Using the transparent adhesive layer 5, the sealing layer 6,which is also transparent, is attached to the information carrier 1. Ifthe information carrier 1 is not part of the enamel protection label,the adhesive layer 5 is implemented as a pressure-sensitive adhesivecoating and is covered with removal material before the enamelprotection label is stuck on.

The label illustrated in FIG. 1 is equipped with a single masking layer7, which is made of transparent plastic film. This masking layer isattached using an adhesive layer 10 to the separating layer 8, which ismade of a transparent UV-cured screenprint enamel. This enamel isapplied using screen printing onto the sealing layer, made of a plasticfilm which is not pretreated using primer, corona discharge, or the likefor the printing. The separating area 9 represents the boundary surfacebetween the separating layer 8 and the sealing layer 6, along which thedetachment for removing the masking layer 7 is performed when theenameling procedure has ended. The separating layer 8 is thereforeremoved together with the masking layer 7. After the masking layer 7 isremoved, the imprint 2 is visible through the sealing layer 6, whichlies protected under the masking layer 7 during the enameling. Theremoval is made easier by the film piece 11, which does not adhere tothe separating layer 8, so that the masking layer 7 may be graspedeasily at this position.

During manufacturing, the masking layer 7, which is provided with theadhesive layer 10, is laminated over the sealing layer 6 printed withthe separating layer 8.

The label illustrated in FIG. 2 has two masking layers 7 a, 7 b and istherefore especially suitable for use in two-stage enameling methods,such as double-layer enameling without further pretreatment orsingle-layer enameling with priming. Analogously constructed enamelprotection labels having three or more masking layers are also possiblewithout problems. The upper masking layer 7 b is attached using anadhesive layer 10 b onto the separating layer 8 b, which is made oftransparent UV-cured screenprint enamel. This enamel is applied usingscreen printing onto the lower masking layer 7 a, made of a plastic filmwhich is not pretreated using primer, corona discharge, or the like forthe printing. The separating area 9 b functionally assigned to the uppermasking layer 7 b represents the boundary surface between the separatinglayer 8 b and the lower masking layer 7 a, along which the detachmentfor removing the upper masking layer 7 b is performed when the enamelingprocedure has ended. The separating layer 8 b is therefore removedtogether with the upper masking layer 7 b. After the upper masking layer7 b is removed, the imprint 2 is visible through the lower masking layer7 a, which lies protected under the masking layer 7 during theenameling, and the sealing layer 6. The position and function of thelower masking layer 7 a, adhesive layer 10 a, separating layer 8 a, andseparating area 9 a functionally assigned to the lower masking layer 7 aremaining after the first method step during and after the second stepof the enameling method is completely analogous to the embodimentdescribed with reference to FIG. 1 and therefore will not be describedagain separately at this point.

A film piece 11 a, 11 b, which is used as a removal aid in the waydescribed above, is assigned to each masking layer 7 a, 7 b.

The label illustrated in FIG. 3 again has two transparent plasticmasking layers 71 a, 71 b and is therefore suitable for two-stepenameling methods. In this case as well, analogously constructedvariations having multiple masking layers for enameling processes havingmultiple steps may be implemented without problems. The upper maskinglayer 71 b is applied directly to the lower masking layer 71 a using thetransparent UV-cured enamel layer 81 b. The lower masking layer 71 a isalso applied directly to the sealing layer 6 using the transparentUV-cured enamel layer 81 a. During manufacturing, each enamel layer 81a, 81 b is first printed on one of the layers which it connects, andthen the particular other layer connected by this enamel layer isapplied and the enamel is subsequently cured under the effect ofultraviolet light.

Either the boundary area 92 b between upper masking layer 71 b andenamel layer 81 b or the boundary area 91 b between enamel layer 81 band lower masking layer 71 a may be functionally assigned to the uppermasking layer 71 b as the separating area. In the first case, the bottomof the upper masking layer 71 b is not pretreated using primer or thelike during manufacturing, in the second case the top of the lowermasking layer 71 a is not pressure pretreated using primer or the likeduring manufacturing. The particular other film area adjoining theenamel layer 81 b may be pretreated in order to achieve better adhesionof the enamel layer 81 b at this point and therefore more defineddetachment behavior at the separating area 91 b and/or 92 b.

Either the boundary area 92 a between lower masking layer 71 a andenamel layer 81 a or the boundary area 91 a between enamel layer 81 aand sealing layer 6 may be functionally assigned to the lower maskinglayer 71 a as a separating area. In the first case, the bottom of thelower masking layer 71 a is not pretreated using primer or the likeduring manufacturing, in the second case the top of the sealing layer 6is not pressure pretreated using primer or the like duringmanufacturing. The particular other film area adjoining the enamel layer81 a may be pretreated in order to achieve better adhesion of the enamellayer 81 a at this point and therefore more defined detachment behaviorat the separating area 91 a and/or 92 a.

In the exemplary embodiment shown in FIG. 3, no separate film piece isprovided as a removal aid, rather the connecting enamel layers 81 a, 81b are each not implemented over the entire area, but leave edge regionsexposed, at which the particular masking layer 71 a, 71 b lyingunderneath may be grasped.

The application in the enameling process is performed analogously in theembodiment shown in FIG. 3 to the exemplary embodiment explained on thebasis of FIG. 2.

1. An enamel protection label for masking text, image, and/or codeinformation (2) in an enameling process, having a transparent sealinglayer (6), a self-adhesive coating (3) positioned underneath the sealinglayer (6), and at least one removable masking layer (7, 7 a, 7 b, 71 a,71 b), which covers the sealing layer (6) at least in the region of thetext, image, and/or code information (2) and is transparent at least inthe region of the coverage of the text, image, and/or code information(2), a separating area (9, 9 a, 9 b, 91 a, 91 b, 92 a, 92 b) of twolayers lying on top of one another being functionally assigned to eachmasking layer (7, 7 a, 7 b, 71 a, 71 b) in such a way that these layerslying on top of one another are separated from one another when themasking layer (7, 7 a, 7 b, 71 a, 71 b) is removed, wherein theseparating area (9, 9 a, 9 b, 91 a, 91 b, 92 a, 92 b) is adhesive-free.2. The enamel protect ion label according to claim 1, wherein one of thelayers lying on top of one another at the separating area (9, 9 a, 9 b,91 a, 91 b, 92 a, 92 b) is made of a transparent enamel, and the otheris made of a plastic film.
 3. The enamel protection label according toclaim 2, wherein the enamel is a UV-cured enamel.
 4. The enamelprotection label according to claim 2, wherein the enamel is appliedusing screen printing, letterpress printing, or flexographic printing.5. The enamel protection label according to claim 2, wherein the enamelis silicone-free.
 6. The enamel protection label according to claim 1,wherein, under the sealing layer (6), a base layer (1) which is gluedthereto is positioned, whose top is provided with the text, image,and/or code information (2) to be covered, and whose bottom carries theself-adhesive coating (3).
 7. The enamel protection label according toclaim 1, wherein the sealing layer (6) carries the self-adhesive coating(5) on its bottom.
 8. The enamel protection label according to claim 1,wherein the enamel protection label has multiple masking layers (7 a, 7b, 71 a, 71 b), which are positioned one on top of another and areremovable one after another.
 9. The enamel protection label according toclaim 1, wherein the sealing layer (6) adjoins the separating area (9, 9a, 91 a) functionally assigned to the proximate masking layer (7, 7 a,71 a) lying above it.
 10. The enamel protection label according to claim1, wherein each masking layer (71 a, 71 b) adjoins the particularseparating area (92 a, 92 b) functionally assigned to it.
 11. The enamelprotection label according to claim 9, wherein each masking layer (7 a,71 a), with the exception of the uppermost masking layer (7 b, 71 b),adjoins the separating area (9 b, 91 b) functionally assigned to theparticular proximate masking layer lying above it.
 12. The enamelprotection label according to claim 11, wherein the bottom of eachmasking layer (7 a, 7 b) adjoins one adhesive layer (10 a, 10 b). 13.The enamel protection label according-to claim 1, wherein the label hasat least one removal aid functionally assigned to each masking layer (7,7 a, 7 b, 71 a, 71 b).
 14. The enamel protection label according toclaim 13, wherein the removal aid is a grip tab shaped onto the maskinglayer (7, 7 a, 7 b, 71 a, 71 b) assigned thereto.
 15. The enamelprotection label according to claim 13, wherein the removal aid is aseparate film piece (11, 11 a, 11 b).
 16. The enamel protection labelaccording to claim 13, wherein the removal aid is manufactured throughadhesive neutralization using partial printing of an adhesive layer (10a, 10 b) adjoining the bottom of the masking layer (7, 7 a, 7 b, 71 a,71 b).
 17. The enamel protection label according to claim 13, wherein anarrow region of locally increased adhesion between the masking layerfunctionally assigned (7, 7 a, 7 b, 71 a, 71 b) to the removal aid andthe film composite lying underneath is positioned near the removal aid.